Submission #1521489

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Source Code Expand

#include <bits/stdc++.h>
#include <math.h>

using namespace std;

typedef pair<int, int> P;

int n;
priority_queue<int> q;
long double ans;
int tmp;

int main() {
  while (cin >> n && n) {
    ans = 0;
    for (int i = 0; i < n; i++) {
      cin >> tmp;
      q.push(tmp);
    }
    while (!q.empty()) {
      if (q.size() == 1) {
        int p = q.top(); q.pop();
        ans += p*p*M_PI;
      }
      int b = q.top(); q.pop();
      int s = q.top(); q.pop();
      ans += b*b*M_PI - s*s*M_PI;
    }
    cout << ans << endl;
    while (!q.empty()) q.pop();
  }
  return 0;
}

Submission Info

Judge Result